The immune system may open the door to recurrent urinary tract infections (UTIs) by overdoing its response to an initial infection, researchers at Washington University School of Medicine in St. Louis have found.
The research was conducted at the Center for Women's Infectious Disease Research at the School of Medicine.
UTIs affect millions of people each year. Although antibiotics are the primary treatment, antibiotic resistance is a growing concern, according to Scott Hultgren, PhD, the center's director. Symptoms include frequent, painful urination, blood or cloudiness in the urine and fatigue.
"Women and infants are at greatest risk for UTIs, and chronic and recurrent infections are common," says Hultgren, the Helen L. Stoever Professor of Molecular Microbiology.
"The diagnosis and treatment of UTIs in the United States is estimated to cost $1.6 billion annually.
In the study, researchers infected mice with UTIs for a month. Some mice spontaneously resolved their infections; others developed a persistent infection that Hultgren's group calls chronic bacterial cystitis. These mice persistently had high levels of bacteria in their urine and bladder and high levels of inflammation in the urinary tract.
"Chronic bacterial cystitis is an infection that is actively reproducing, has established a persistent and significant foothold in the host's bladder and has prompted a sustained response from the immune system," says Hannan, a research instructor in pathology and immunology.
"Despite all this, the infection is still well-tolerated by the mice."